Aomori Prefecture Research Articles

Where are you from? A case study of Japanese Spanish mackerel using Anisakis third-stage larvae as a biological tag in coastal northeast Aomori Prefecture, Japan

Where are you from? A case study of Japanese Spanish mackerel using Anisakis third-stage larvae as a biological tag in coastal northeast Aomori Prefecture, Japan

Predation of salamander egg sacs by the water strider Gerris (Macrogerris) insularisMotschulsky (Hemiptera: Gerridae)

AbstractWater striders (Hemiptera: Gerridae) are sucking predators that inhabit freshwater and marine environments. They prey mainly on insects that fall on the water surface, but they are also known to feed on amphibian eggs. Here, we report on the predation of egg sacs of Hynobius nigrescens (Caudata: Hynobiidae) by Gerris (Macrogerris) insularis. We observed predation on egg sacs of H. nigrescens by G. insularis at a pond in a mountainous area of Nagano City, Nagano Prefecture, Japan. We also found egg sacs with predation marks probably made by water striders at a pond in the mountainous area of Nishimeya Village, Aomori Prefecture, Japan. Five water striders collected around the preyed egg sacs were identified as G. insularis. We filled three tanks with water and an egg sac, and three water striders that were collected at the site in Nishimeya Village were placed together in each tank. In two tanks, the jelly layer of the egg sac was partially cut in a horizontal manner, while in another tank, the jelly layer was removed on the part of the egg sac exposed on the water surface. Notably, the water striders exhibited predatory behavior only when the jelly layers were removed. Considering the results of the rearing experiment and the predation marks observed in the field, G. insularis is also likely to prey on egg sacs at the site in Nishimeya Village. Our study suggested that predation by G. insularis occurs when eggs are accidentally exposed due to disturbance of the jelly layer.

Utility of the rurality index for Japan for exploring good practice solutions for declining birthrates in rural areas

AbstractBackgroundJapan is experiencing unprecedented decreasing birthrates. This preliminary study aimed to identify the municipalities in Aomori Prefecture that are successfully tacking declining birthrates using the Rurality Index for Japan (RIJ).MethodsWe obtained 100‐level RIJ and census data from 1980 to 2020 for children (age < 15 years) in the municipal population of Aomori Prefecture.ResultsThe analysis revealed generally weak but significant relationships between population variables and the RIJ.ConclusionsThe RIJ is effective for identifying good practice communities that have developed and implemented solutions to prevent declining birthrates at the community level.

Collaboration between Primary Care Physicians and the Local Government for Long-term Care and Prevention Based on Community Diagnosis in Sannohe Town, Aomori Prefecture, Japan

Collaboration between Primary Care Physicians and the Local Government for Long-term Care and Prevention Based on Community Diagnosis in Sannohe Town, Aomori Prefecture, Japan

Dune soil nitrogen leaching for Chinese-yam cultivation: Impact of microbe-decomposable slow-release fertilizer

Chinese yam production is thriving in Aomori Prefecture, a cold and snowy region in Japan. Recently, there has been an increasing risk of nitrogen leaching in Chinese-yam fields, which consist of sandy soil, due to localized torrential rain. The relationships between the type of fertilizer used for Chinese-yam cultivation, the amount of nitrogen (N) leaching, and the timing of leaching remain unknown. Therefore, this study aimed to fill this knowledge gap by investigating the effects of different fertilizers (fast-acting and/or slow-release fertilizer) and irrigation practices (conventional and/or excessive irrigation) in order to mitigate the detrimental impact of nitrogen leaching on groundwater quality. An enhanced mathematical model and the spatiotemporal dynamics of inorganic nitrogen concentration in soil pore water were evaluated the negative impact of nitrogen leaching on the groundwater environment was evaluated. The results showed that the combined use of slow-release fertilizers could significantly reduce nitrate-nitrogen concentration in soil-water, especially during the harvest season. This study demonstrated that cultivating Chinese yam with a fertilizer application system that includes the use of slow-release fertilizer can diminish the negative impact of nitrogen leaching on the groundwater environment, contributing to our understanding of sustainable agricultural practices in regions facing similar environmental challenges. Therefore, our findings represent an important advancement providing new approaches to maintaining productivity while mitigating the adverse impacts on groundwater environments, as well as offering guidelines for agricultural practices in regions facing similar environmental challenges.

Factors Affecting Outcomes of Poor-Grade Subarachnoid Hemorrhage

Poor-grade subarachnoid hemorrhage (SAH) accounts for 20% of all SAH and is associated with poor outcomes. The first step in improving outcomes is to analyze the factors that contribute to poor outcomes. This was a multicenter, retrospective, observational, cohort study. Data fields included demographic, clinical, radiological, and outcome data for all spontaneous patients with SAH treated at 4 hospitals in Aomori Prefecture in Japan. Patients with modified Rankin Scale score 0-2 at discharge were defined as the good outcome group, and those with modified Rankin Scale score 3-6 were defined as the poor outcome group, and comparisons were made between the 2 groups. There were 329 eligible patients with poor-grade SAH, 41 with good outcome group, and 288 with poor outcome group. On multivariate analysis of the outcome, conservative treatment (P < 0.001), Fisher group 4 (P < 0.007), age ≥65 years (P= 0.011), and Hunt and Kosnik grade V on admission (P= 0.021) were significant factors contributing to a poor outcome. Nonelderly patients who are not in grade V and Fisher group 4 should undergo aneurysm treatment as soon as possible because they are more likely to have a good outcome, whereas elderly patients in grade V and Fisher group 4 are unlikely to benefit from aneurysm treatment at present. The development of a treatment for early brain injury may be important to improve the outcomes of patients with poor-grade SAH.

Sacralizing the Playful Secular: The Deity of Karuta-Gambling at the Nose Kannon Hall in Sannohe, Aomori

In a faraway apple orchard in Sannohe, a small town in Japan’s Aomori Prefecture, a zushi miniature wooden shrine at the Nose Kannon Hall caught the media’s attention with its unique adornment—the karuta playing cards with European-inspired abstract designs in bold red and black colors that were used during the early modern period for pastime and gambling. Because of this decoration, the Nose Kannon Hall is known by locals as the Karuta Hall, and the zushi that enshrines the Buddhist deity Bodhisattva Shō-Kanzeon is also believed to be the home of bakuchi no kamisama “the kami deity of gambling”. Little is known about the nature of devotion to this bakuchi no kamisama or how the playing cards that were used for frivolous games came to be sacralized as items worthy to be used as decoration of a Buddhist shrine. This article considers the slippage between prayer and play in the regional Buddhist devotion by focusing on the Nose Kannon Hall, which presided at a key intersection along the northern trade route where the local community and outside visitors, such as pilgrims and traders, converged, especially during the Edo period (1603–1868). Marshaling historical records, televised interviews, and images provided by the town officials and guardian family of Nose Kannon Hall, I argue that the use of karuta playing cards on the miniature shrine at Nose Kannon Hall epitomizes a kind of localized early modern Shinto–Buddhist syncretism at the margins of the urban culture that is simultaneously devotional and tongue-in-cheek sacrilegious in a quintessentially Edo-esque way.

Precipitation and Moisture Transport of the 2021 Shimokita Heavy Precipitation: A Transformed Extratropical Cyclone from Typhoon#9

This study examines the heavy rainfall event that occurred in the Shimokita Peninsula, Japan, on 9–10 August 2021, resulting from an extra-tropical cyclone that developed from Typhoon#9 (EC9). The objective of this study is to elucidate the relationship between moisture transport and heavy rainfall and to verify the role of EC9. The authors created intensive hourly precipitation data over the Aomori Prefecture and analyzed them together with moisture fields. In most locations where the landslide disaster occurred, there were two precipitation peaks: at 9 UTC and 18 UTC on 9 August. The wind shear was strong from the lower to the upper troposphere with easterly winds in the lower troposphere and warm moist air from south for the first peak. A strong horizontal gradient of equivalent potential temperature, a northerly in lower troposphere, and moisture convergence over Shimokita Peninsula indicate the existence of the stationary front for the latter peak (18 UTC). The heavy precipitation and moisture convergence that caused the Shimokita event were identified by the stationary front of EC9 around the latter peak (15 UTC of 9th–06 UTC of 10 August). The precipitation distribution, which has a precipitation peak northeast of the EC center, is a typical typhoon-turned extratropical cyclone (EC) precipitation distribution.

Intermittent hydrothermal alteration and silicification of black mudstones found in the Middle to Upper Miocene Yagen Formation, Shimokita Peninsula, Northeast Japan

AbstractOrganic geochemical processes in hydrothermal alteration system in terrestrial areas were investigated in the Shimofuro geothermal field, Northeast Japan. This study describes a continuous long mudstone outcrop of the Middle to Late Miocene Yagen Formation on the Shimokita Peninsula, Aomori Prefecture. The outcrop located near Mt.Hiuchi‐dake shows sequential alteration with a color change from black to white. Contents of total organic carbon (TOC) vary from 0.00% to 0.46% according to litho‐color change and become higher for black and lower for gray to white. TOC contents show a negative correlation with SiO2 concentration. These indicate that TOC contents in the outcrop strongly depend on silicification caused by hydrothermal alteration. The mineral assemblages are composed of alunite, kaolinite, illite and pyrite, and indicate distinct alteration zones with acidic to neutral hydrothermal activities. Composition of the minerals formed by the alteration suggests that the temperature of hydrothermal fluid ranged from 150 to 250°C in a high‐sulfidation hydrothermal system. Regarding the extracted hydrocarbons, particularly n‐alkane distributions are significant. Values of Carbon Preference Index (CPI) increase up to 2.8 with increasing alteration and with decreasing TOC contents. This can be explained by two processes, (1) at the site of highly hydrothermal alteration, thermal cracking of organic matter in black mudstone strongly occurred and produced low‐molecular gaseous hydrocarbons, and (2) at the site of inner rock with a distance from the hydrothermal alteration, thermal cracking moderately occurred and produced medium to long chain n‐alkanes which were overlapped with original n‐alkanes. Very low Tmax values were found at the hydrothermal zone. This implies that natural extraction, migration, and precipitation of bituminous organic matter were driven by hydrothermal fluid.

Risk Factors Contributing to Disparities in Medical Treatment and Lower Survival Rates among Patients with Non-Small Cell Lung Cancer Induced by Residential Areas.

Because of a lack of medical resources for cancer treatment, particularly in rural areas, there are disparities in receiving medical treatment between urban and rural area. This study examined the association between residential area or areal deprivation index (ADI) and lack of surgical treatment or chemotherapy in patients with non-small cell lung cancer (NSCLC) in rural area, Japan. We analyzed the Aomori population-based cancer registry data from 926 cancer patients with NSCLC diagnosed between January and December 2014. Multivariable logistic regression and Cox proportional hazards models were used to examine association of patients' residential area/ADI with either surgery/chemotherapy or survival time, respectively. The residential area was divided into six medical areas based on the location of specialist hospitals. The medical areas were defined by Aomori Prefecture. The residential area (medical area) was strongly associated with access to cancer treatment for patients with NSCLC and ultimately contributed to lower survival rates. There was no significant influence in the distance from home to hospital and areal deprivation. We identified the risk factors related to a lack of medical treatment and shorter survival in rural area, Japan.

Re-evaluation of chronostratigraphy of the Neogene system, distributed in western Shimokita Peninsula, Aomori Prefecture and proposal of Hotokegaura Caldera

Re-evaluation of chronostratigraphy of the Neogene system, distributed in western Shimokita Peninsula, Aomori Prefecture and proposal of Hotokegaura Caldera

A study on the coloration mechanism of Ao-ike Pond, Aomori Prefecture, Japan: refinement of the image analysis methods

A study on the coloration mechanism of Ao-ike Pond, Aomori Prefecture, Japan: refinement of the image analysis methods

Transfer of 137Cs and 90Sr from soil-to-potato: Interpretation of the association from global fallout in Aomori to accidental release in Fukushima and Chornobyl

Ceasium-137 and 90Sr are major artificial radionuclides that have been released into the environment. Soil-to-plant transfer of radionuclides is an important route to food contamination. The radionuclide activity concentrations in crops must be quantitatively predicted for estimating the internal radiation doses from food ingestion. In this study, soil and potato samples were collected from three study sites contaminated with different sources of 137Cs and 90Sr: Aomori Prefecture (global fallout) and two accidental release areas (Fukushima Prefecture and the Chornobyl exclusion zone). The 137Cs activity concentrations in the soil and potato samples widely ranged from 1.0 to 250,000 and from 0.048 to 200,000 Bq kg−1 dry weight, respectively. The soil-to-potato transfer factor of 137Cs also ranged widely (0.0015–1.1) and decreased with increasing concentration of exchangeable K. Meanwhile, the activity concentrations of 90Sr in the soil and potato samples were 0.50–64,000 and 0.027–18,000 Bq kg−1 dry weight respectively, and the soil-to-potato transfer factor of 90Sr was 0.023–0.74, decreasing with increasing concentration of exchangeable Ca. The specific activity ratios of 137Cs/Cs and 90Sr/Sr in the exchangeable fraction were similar to those in potatoes, with a factor of 3 in the ±95 % confidence intervals over six orders of magnitude and a factor of 2 in the ±95 % confidence intervals over five orders of magnitude, respectively. According to the data, the accuracy of predicting the activity concentrations of 137Cs and 90Sr in potatoes can be improved by applying the specific activity ratios of 137Cs/Cs and 90Sr/Sr in the exchangeable fraction. This approach accounts for variable factors such as the effects of K and Ca fertilization and soil characteristics. It also emphasizes the benefit of determining the stable Cs and Sr concentrations in potatoes and other crops prior to possible future contamination.

Applicability of data envelopment analysis using vessel-level data to the estimation of technical efficiency and capacity utilization of the small-scale squid angling fishery in Aomori Prefecture, Japan

Applicability of data envelopment analysis using vessel-level data to the estimation of technical efficiency and capacity utilization of the small-scale squid angling fishery in Aomori Prefecture, Japan

Dynamics of haplotypic variation across geographic populations of Venturia inaequalis in Aomori Prefecture, Japan, determined using microsatellite markers

Dynamics of haplotypic variation across geographic populations of Venturia inaequalis in Aomori Prefecture, Japan, determined using microsatellite markers

Plane‐strain model for large strain consolidation induced by vacuum‐assisted prefabricated horizontal drains

AbstractVacuum‐assisted prefabricated horizontal drain (PHD) can be used to accelerate the consolidation process of dredged mud slurry with high water content, and this method exhibits advantages over traditional treatment methods that use prefabricated vertical drain (PVD). However, large‐strain model that can simulate soil consolidation induced by vacuum‐assisted PHDs is missing in the literature, although the large‐strain models for PVD‐induced radial consolidation are abundant. This study presents a piecewise‐linear plane‐strain model for large‐strain consolidation induced by vacuum‐assisted prefabricated horizontal drains. The model is called PCS, abbreviation for Plane‐strain Consolidation Settlement. PCS model can account for complex conditions including large strain, multiple layers of PHD boards, staged filling of soil layers, varying spacing of PHD boards, time‐dependent surcharge and/or vacuum loading, soil self‐weight, nonlinear compressibility, and hydraulic conductivity during the consolidation process, vertical and horizontal flows, and non‐Darcian flow. The PCS is validated using the two‐dimensional Terzaghi's consolidation theory (small strain) and a large‐scale laboratory model test (large strain), which involves multiple soil layers filled in stages, multiple PHD layers, and different horizontal spacings of PHD boards. Lastly, the proposed model is applied to a case study conducted at Shimokita Peninsula (Aomori Prefecture, Japan), where vacuum‐assisted PHDs have been used to treat the dredged mud slurry for a duration of 330 days.

Holocene drift pumices and their source volcanoes at Sekinehama, Mutsu City, Aomori Prefecture, Japan

青森県むつ市関根浜に露出する完新世堆積物から多数の軽石（SKN-1～6）を見出した．このうち2層の軽石濃集層（SKN-2とSKN-3）は，それぞれ鬱陵島U-2テフラ（U-2）と十和田中掫テフラ（To-Cu）の軽石で構成されていた．SKN-2とSKN-3は層相と層序，軽石の粒径・形状から，海域での漂流を経て堆積した漂着軽石と考えられる．また，SKN-2とSKN-3は，有機質シルト・泥炭層中に存在することと約6 kaの海水準や地形を考慮すると，海と繋がる小河川を経て潟湖に漂着したものと推測される．加えて，水平方向に連続的に堆積する様相は堆積当時の汀線付近に多数の軽石が分布していたことを示唆する．

The second phantom aquatic leaf beetle in Japan: Macroplea mutica rediscovery in the wetlands (Coleoptera: Chrysomelidae)

AbstractWetland biodiversity is currently declining on a global scale. Wetland biodiversity understanding is critical for determining the wetlands' conservation value. In this study, Macroplea Samouelle, 1819 (Coleoptera: Chrysomelidae) was discovered in Aomori Prefecture, Honshu Island, Japan. Only two Macroplea species have been recorded in Japan, M. japana (Jacoby, 1885) and M. mutica (Fabricius, 1792). Macroplea japana had been unrecorded for 60 years before being rediscovered in Honshu Island in 2022, and a single adult M. mutica female was discovered in Hokkaido Prefecture in 2003. The discovered individuals were concluded to be M. mutica based on morphological and molecular analyses. Although morphological differences were observed with the Eurasian M. mutica individuals, the male genitalia was nearly identical to M. mutica. For the molecular phylogenetic analysis based on COI and 28S sequences, Macroplea individuals in Japan were clustered with M. mutica on the Eurasian Continent. This is the first record of this species on Honshu Island (and the second in Japan), as well as the first record of adult males. This species would require conservation policies and additional distributional surveys.

Isotopic Diet Analysis of the Japanese Water Shrew Chimarrogale platycephala to Estimate Their Feeding Habits and the Usefulness of Body Hair Samples

The water shrew Chimarrogale platycephala is an endangered species in Japan. Although immediate conservation actions are necessary, detailed information on this species is inadequate. We compared dietary trends obtained via C. platycephala digestive contents analysis with those through stable isotope analysis (δ13C, δ15N, ‰) of non-invasive body hair and invasive muscles to elucidate their diet and evaluate usefulness of the dietary stable isotope analysis. We captured 20 shrews from three streams in Aomori Prefecture from 2013 to 2016 barring snow accumulation seasons. The digestive contents analysis showed that water shrews mainly fed on aquatic insects, whereas freshwater crabs, fishes, and terrestrial insects were also observed as diets. δ13C values from the stable isotope analysis were not significantly different between muscles and body hair and indicated a primary diet of aquatic invertebrates and fishes. δ15N values were significantly lower in muscles and indicated a similar trophic position of water shrews to fishes. In the isotope mixing model, the contribution of terrestrial invertebrates was less than 0.35 except for two individuals that showed the highest terrestrial invertebrate ratio (> 0.5) and the lowest aquatic invertebrate ratio. This study also demonstrated that body hair from any part of the back was sufficiently useful for dietary stable isotope analysis.

Economic performance of small-scale squid angling fishery under the poor catch problem: the case of fishery in Aomori Prefecture

Economic performance of small-scale squid angling fishery under the poor catch problem: the case of fishery in Aomori Prefecture